1. Field of the Invention
The invention generally relates to a polishing pad and a method of manufacturing the same, and more particularly to a polishing pad having a detection window and a method of manufacturing the same.
2. Description of Related Art
Along with advancement of the industries, planarization processes are often adopted as processes for manufacturing various devices. In planarization processes, polishing process is often used in the industries.
Generally, polishing process applies a pressure on an article to be polished so as to press the article onto a polishing pad, and provides a relative movement between the article and the polishing pad. Through mechanical friction generated by the relative movement, a portion of a surface layer on the article is removed, so that the surface is gradually planarized, thereby achieving the purpose of planarization. Optionally, polishing solution or polishing slurry containing chemical composition can be applied on the polishing pad during polishing process, such that the surface of the article is planarized under the synergy of mechanical effect and chemical effect.
For a polishing apparatus with an optical detection system, a transparent detection window is usually disposed on a region of the polishing pad. By detecting the polishing condition on the surface of the article through the transparent detection window with the optical detection system, user can determine an end-point detection of the polishing process.
In a conventional method of manufacturing a detection window on a polishing pad, a polishing pad is first manufactured and a detection opening is formed on the polishing pad by mechanical cutting. Thereafter, a detection window material is filled into the detection opening and a curing process is carried out for curing the detection window material to form a detection window. However, in this method, the detection opening is formed on the polishing pad by mechanical cutting, such that an additional cutting procedure is required and the time required for manufacturing the polishing pad is increased. As this method requires additional mechanical cutting tool, the manufacturing cost may also be higher.
In another conventional method of manufacturing a detection window on a polishing pad, the detection window is first formed and placed in a mold. Then, a polishing pad material is filled into the mold and then a curing process is performed, so that the polishing pad having the detection window is formed. Nevertheless, the bonding strength between the polishing pad and the detection window formed by this method is insufficient. In other words, using the polishing pad formed by the aforementioned method applying to a longer polishing time accumulated, liquid tends to penetrate through a boundary between the polishing pad and the detection window to the optical detection system. Consequently, the end-point detection of the polishing is interfered so as to affect the polishing quality of the article.